a transition from ground to surface water consumption, effectively halted subsidence in the most severe areas near the Ship Channel; aquifer recharge has helped water table elevations return to normal. However, in the northwestern region of the city, groundwater levels – and, concurrently, land surface elevations – continue to decline. Cityscape When Houston was established in 1837, the city's founders—John Kirby Allen and Augustus Chapman Allen—divided it into political geographic districts called "wards." The ward designation is the progenitor of the current-day Houston City Council districts—there are nine in all. Locations in Houston are generally classified as either being inside or outside Interstate 610, known as the "610 Loop" or simply "The Loop". Inside the loop generally encompasses the central business district, and has come to define an urban lifestyle and state of mind. Elizabeth Long, the author of the 2003 book Book Clubs: Women and the Uses of Reading in Everyday Life, wrote that most of the upper middle classes in the 610 Loop live in the southwestern part of the inner city in the areas near Hermann Park, the Houston Museum District, Rice University, and the Texas Medical Center, while some portions of northern Houston and Eastern Houston have been gentrified and also have upper middle classes. The outlying areas of Houston, the airports, and the city's suburbs and enclaves are outside the Loop. Another ring road, Beltway 8 (also known simply as the "Beltway" or as the "Sam Houston Tollway"), encircles the city another 5 miles (8 km) farther out. Parts of Beltway 8 are toll roads, but for most of the route, motorists can drive in the adjacent "feeder" or service roads at no charge. Farm to Market Road 1960 (FM 1960) forms a semicircle in northern Houston and is another dividing line. The third ring road, State Highway 99 (also known as the Grand Parkway), is under construction. Long stated that most of the wealthier Houston suburbs are west and north of the central city, while to the southeast the Clear Lake/NASA "[represents] another burgeoning concentration of largely aerospace-related prosperity". Houston, being the largest city in the United States without zoning laws, has grown in an unusual manner. Rather than a single "downtown" as the center of the city's employment, five additional business districts have grown throughout the inner city—they are Uptown, Texas Medical Center, Greenway Plaza, Westchase, and Greenspoint. If these business districts were